<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

        .clock {
            width: 200px;
            height: 200px;
            border: 5px solid red;
            /* 圆角 */
            border-radius: 50%;
            /* 相对定位 */
            position: relative;
        }

        /* 水平垂直居中 定位的固定写法 */
        .num {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }

        /* 权重: 10 + 10 */
        .num:nth-child(1) {
            /*
                1. 回调-50% 为了居中
                2. 旋转固定角度
                3. 向上发射80px
                4. 转回原来的角度
            */
            transform: translate(-50%, -50%) rotate(30deg) translateY(-80px) rotate(-30deg);
        }

        .num:nth-child(2) {
            transform: translate(-50%, -50%) rotate(60deg) translateY(-80px) rotate(-60deg);
        }

        .num:nth-child(3) {
            transform: translate(-50%, -50%) rotate(90deg) translateY(-80px) rotate(-90deg);
        }

        /* 更多... */

    </style>
</head>
<body>
    <div class="clock">
        <div class="num">1</div>
        <div class="num">2</div>
        <div class="num">3</div>
    </div>
</body>
</html>